Sequential Inter-institutional Discordance in Auditory Brainstem Response Thresholds During Medicolegal Hearing Disability Evaluation

Background: Auditory brainstem response (ABR) testing is widely used to objectively evaluate medicolegal hearing disability.However, the consistency of ABR threshold measurements across institutions remains insufficiently characterized.This study aimed to quantify sequential inter-institutional discordance in ABR thresholds and to examine its implications for medicolegal hearing disability evaluation.Methods: This retrospective observational study included 103 patients (206 ears) who underwent sequential ABR testing at two distinct institutions during medicolegal hearing disability evaluation.Agreement between the sequential ABR thresholds was assessed using the intraclass correlation coefficient (ICC), Bland-Altman analysis, and Pearson correlation.Absolute inter-institutional differences were quantified, and mixed-effects modeling was used to decompose variance and estimate the institution-associated component.Additional sensitivity analyses evaluated the potential impact of bilateral inclusion and patient-level clustering.Results: Overall agreement between the sequential ABR thresholds was moderate (ICC(2,1) = 0.522).The mean inter-institutional bias was +0.05 dB; however, the Bland-Altman limits of agreement were wide (-29.0 to +29.1 dB).The mean absolute inter-institutional difference was 11.3 dB, with differences > 10 dB observed in 37.9% of ears.The institution-associated